U.S. patent application number 10/706417 was filed with the patent office on 2004-08-26 for azo metal-complexed dyes, ink jet ink compositions and ink jet printing methods.
Invention is credited to Berger, Michael J., Filosa, Michael P., Stroud, Stephen.
Application Number | 20040163568 10/706417 |
Document ID | / |
Family ID | 32313032 |
Filed Date | 2004-08-26 |
United States Patent
Application |
20040163568 |
Kind Code |
A1 |
Berger, Michael J. ; et
al. |
August 26, 2004 |
Azo metal-complexed dyes, ink jet ink compositions and ink jet
printing methods
Abstract
There are described metal-complexed azo dyes which are useful in
ink jet printing applications. Also described are ink jet ink
compositions including a dye of the invention as well as ink jet
printing methods and apparatus.
Inventors: |
Berger, Michael J.;
(Chestnut Hill, MA) ; Filosa, Michael P.;
(Medfield, MA) ; Stroud, Stephen; (Medford,
MA) |
Correspondence
Address: |
POLAROID CORPORATION
Patent Department
1265 Main Street
Waltham
MA
02451
US
|
Family ID: |
32313032 |
Appl. No.: |
10/706417 |
Filed: |
November 12, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60425650 |
Nov 12, 2002 |
|
|
|
Current U.S.
Class: |
106/31.5 ;
347/100; 534/710 |
Current CPC
Class: |
C09B 45/14 20130101;
C09D 11/328 20130101; C09D 11/037 20130101 |
Class at
Publication: |
106/031.5 ;
347/100; 534/710 |
International
Class: |
C09D 011/02; B41J
002/01; C09B 045/00 |
Claims
What is claimed is:
1. A printing ink composition comprising a metal-complexed dye
represented by the formula 5or a salt thereof wherein: M is a
metal; R.sub.1 and R.sub.2 each independently is a solubilizing
group; R.sub.3 is selected from the group consisting of: (1) alkyl;
(2) cyano; (3) COOH; and (4) CONH.sub.2; X.sub.1 and X.sub.2 each
independently is a counterion; Z is a ligand; n is an integer of
from 1 to 3; m is an integer of from 1 to 3; and p is an integer of
from 1 to 3; dissolved or dispersed in a liquid carrier.
2. The printing ink composition according to claim 1 wherein said
liquid carrier comprises water.
3. The printing ink composition according to claim 1 wherein M is
copper.
4. The printing ink composition according to claim 1, wherein at
least one of X.sub.1 and X.sub.2 is an alkali metal ion.
5. The printing ink composition according to claim 1 which includes
a dye represented by the formula 6wherein R.sub.5 is alkyl and M,
R.sub.1, R.sub.2, X.sub.1, X.sub.2, Z. m, n and p are as defined in
claim 1.
6. The printing ink composition according to claim 1 which includes
a dye represented by the formula 7
7. An ink jet ink comprising a solution of a dye according to claim
1 in water, aqueous alcohol or an aqueous glycol.
8. A printing ink composition comprising a metal-complexed dye
represented by the formula 8wherein: M is a metal; R.sub.1 and
R.sub.2 each independently is a solubilizing group; R.sub.3 is
selected from the group consisting of: (5) alkyl; (6) cyano; (7)
COOH; and (8) CONH.sub.2; X.sub.1 and X.sub.2 each independently is
a counterion; n is an integer of from 1 to 3; and m is an integer
of from 1 to 3; dissolved or dispersed in a liquid carrier.
9. The printing ink composition according to claim 8 wherein said
liquid carrier comprises water.
10. The printing ink composition according to claim 8 wherein M is
copper.
11. The printing ink composition according to claim 8 wherein at
least one of X.sub.1 and X.sub.2 is an alkali metal ion.
12. An ink jet cartridge comprising a housing having walls defining
a reservoir and an outlet opening, the cartridge containing an ink
jet ink according to claims 1 or 8.
13. An ink jet printing method comprising forming a plurality of
drops of an ink composition, and directing said drops onto an ink
receptive material to form an image thereon, wherein said ink
composition is according to claims 1 or 8.
14. A metal-complexed dye represented by the formula 9where M is a
metal; R.sub.1 and R.sub.2 each independently is a solubilizing
group; R.sub.5 is alkyl; X.sub.1 and X.sub.2 each independently is
a counterion; Z is a ligand; n is an integer of from 1 to 3; m is
an integer of from 1 to 3; and p is an integer of from 1 to 3.
15. A metal-complexed dye according to claim 14 wherein R.sub.5 is
methyl.
16. A metal-complexed dye according to claim 15 wherein M is
copper.
Description
REFERENCE TO RELATED APPLICATION
[0001] This application claims the benefit of prior provisional
application serial No. 60/425,650, filed Nov. 12, 2002.
FIELD OF THE INVENTION
[0002] This invention relates to metal-complexed azo dyes and to
printing ink compositions for use in ink jet printers. More
specifically, this invention relates to certain metal-complexed azo
dyes and to ink jet ink compositions which include metal-complexed
azo dyes, or their salts, which possess a combination of
characteristics rendering them especially useful in such inks. The
invention also relates to ink jet printing methods.
BACKGROUND OF THE INVENTION
[0003] Ink jet printers are commonly used as hard copy output
devices for computers. Such printers form an image by using a
plurality of nozzles to form a stream of droplets of an ink and to
direct those droplets on to a sheet of an ink receiving medium
(typically a surface-treated paper), thus forming the image. The
image may be a monochrome image, formed using a single, normally
black, ink, or a full color image, formed using at least three inks
of differing colors sprayed from a set of three separate nozzles.
Some contemporary ink jet printers are capable of producing color
images of photographic or near-photographic quality, and are often
used by graphic artists to obtain rapid color proofs of
illustrations which closely simulate the color illustration which
will eventually be produced on a conventional printing press. Ink
jet printers can also make use of more than four inks (for example,
eight color CCMMYYKK printers are produced commercially) by
providing the appropriate number of sets of nozzles, and permit
relatively easy use of custom-blended inks when such custom inks
are required for particular jobs.
[0004] Although so-called "solid ink jet" printers are known using
"inks" which are solid at room temperature and which are melted
before being sprayed in the liquid state, most ink jet printers are
of the so-called "liquid ink jet" type and use inks which are
liquid at room temperature. Such inks typically comprise a dye
dissolved, or dispersed, in a solvent or suspension medium. The
solvent or medium may be organic, but organic solvents are
generally not favored because of environmental and toxicity
problems, and hence most solvents or suspension media are aqueous,
although they may contain an alcohol or a glycol as a co-solvent.
Liquid inks may also contain other additives, such as stabilizers,
viscosity modifiers, surfactants, bactericides, fungicides etc.
[0005] The dyes used in such liquid inks must satisfy numerous
requirements. In order to produce images with the wide range of
colors and highly saturated colors demanded by graphic artists, the
dyes should have high extinction coefficients and good color. The
dyes need to be highly soluble (or dispersible) in the solvent or
carrier medium used, since an insufficiently soluble dye requires
spraying an excessive amount of solvent with the dye, thus leading
to undesirably slow drying of the image on the receiving sheet. The
dye solution must be stable over the wide ranges of temperature and
humidity likely to be encountered during distribution and storage
of the ink, since even modest precipitation of solid dye crystals
from the solution/dispersion will be disastrous because the narrow
nozzles are readily clogged by such crystals. Finally, the color of
the dyes, and thus of the image, must be essentially unaffected by
(a) chemical reactions between the dye and any one of the variety
of receiving sheets on which the image may be formed; (b) chemical
reactions between the dye and any other dyes used to form the same
image (in color ink jet printing, drops of the various colored inks
inevitably come into contact on the receiving sheet, especially in
areas of high color density); (c) air oxidation of the final image;
and (d) photochemical reactions when the image is exposed to
radiation. For obvious reasons, a graphic artist does not want a
proof prepared for a client to undergo noticeable fading or color
shifts simply because the client leaves the proof exposed on a
desktop under office fluorescent lighting, or takes the proof
outdoors for a short time in order to view it in daylight.
[0006] All these requirements tend to produce dyes which are a
compromise, excellence in one property being sacrificed for
acceptable behavior in another. In particular, many commercial ink
jet dyes have less photostability than is desirable, and are
subject to significant fading when exposed to office fluorescent
lighting for lengthy periods.
[0007] Various pyrazolone dyes are known in the art. Patel et al.,
in Pyrazolone Dyes and Their Complexes For Use On Synthetic Fibers,
J. Institute of Chemistry (India), (1999) teach certain metal
complexed pyrazolone dyes for use in dyeing textiles.
[0008] As the state of the art advances and efforts are made to
provide new ink jet recording systems which can meet new
performance requirements and to reduce or eliminate some of the
aforementioned undesirable characteristics of the known systems it
would be advantageous to have new dyes which are useful in ink jet
ink compositions and new ink jet ink compositions which can provide
images which exhibit enhanced stability to light and ozone.
SUMMARY OF THE INVENTION
[0009] It is therefore an object of this invention to provide novel
metal-complexed azo dyes.
[0010] It is another object to provide novel printing ink
compositions.
[0011] It is another object of the invention to provide printing
ink compositions which are useful in ink jet imaging
applications.
[0012] Another object of the invention is to provide printing ink
compositions which include metallized azo dyes.
[0013] A further object of the invention is to provide ink
compositions for use in ink jet imaging applications which can
provide appropriate chroma and hue angle on a variety of receiver
materials.
[0014] Still another object of the invention is to provide ink jet
imaging methods.
[0015] These and other objects and advantages are accomplished in
accordance with one embodiment of the present invention by
providing printing ink compositions which comprise metallized azo
dyes, or salts thereof. The dyes may be 1:1 metal complexes or 2:1
metal complexes.
[0016] The 1:1 metal complexed dyes are represented by formula I
illustrated below 1
[0017] wherein
[0018] M is a metal such as, for example, copper, chromium, cobalt,
nickel or the like;
[0019] R.sub.1 and R.sub.2 each independently is a solubilizing
group such as, for example, sulfonate (SO.sub.3.sup.-), carboxylate
(COO.sup.-), SO.sub.2NH(CH.sub.2).sub.3N.sup.+(R.sub.4).sub.3, or
the like, where R.sub.4 is alkyl having from 1 to 3 carbon
atoms;
[0020] R.sub.3 is selected from the group consisting of:
[0021] (1) alkyl, preferably having from 1 to 6 carbon atoms,
[0022] (2) cyano;
[0023] (3) COOH; and
[0024] (4) CONH.sub.2;
[0025] X.sub.1 and X.sub.2 each independently is a counterion which
may be a cation such as, for example, an alkali metal such as
lithium, sodium or potassium or a quaternary ammonium moiety or an
anion such as a halogen, for example, chloride or bromide or an
alkyl sulfonate;
[0026] Z is a ligand which may be H.sub.2O or a solvent such as an
aqueous alcohol, e.g., methanol, an aqueous glycol, acetonitrile,
dimethylformamide or the like;
[0027] n is an integer of from 1 to 3;
[0028] m is an integer of from 1 to 3; and
[0029] p is an integer of from 1 to 3.
[0030] The 2:1 metal complexed dyes are represented by formula II
illustrated below 2
[0031] wherein M, R.sub.1, R.sub.2, R.sub.3, X.sub.1, X.sub.2, m
and n are as previously defined.
[0032] The ink jet ink compositions of the invention comprise a
solution of at least one dye of the invention in a suitable vehicle
such as water, aqueous alcohol, aqueous glycol, etc. The invention
also includes an ink jet cartridge comprising a housing having
walls defining a reservoir and an outlet opening, the cartridge
containing an ink composition of the present invention.
[0033] There are also provided according to the invention, ink jet
printing methods comprising forming a plurality of droplets of an
ink composition of the invention, and directing these droplets onto
a receiver material to form an image thereon.
[0034] In another embodiment of the invention there are provided
novel metal-complexed azo dyes which are represented by the formula
3
[0035] where R.sub.5 is alkyl, preferably having from 1 to 6 carbon
atoms, and particularly preferably methyl; and M, R.sub.1, R.sub.2,
X.sub.1, X.sub.2, Z, m, n and p are as previously defined.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0036] A particularly preferred compound of the invention is a
yellow dye represented by the formula 4
[0037] The dye of formula IV, when utilized in ink jet printing ink
compositions, has been found to provide images on various ink jet
receiver materials which exhibit good luminance, chroma and hue and
good light stability and resistance to ozone. Thus, a particularly
preferred ink jet ink composition of the invention includes a dye
represented by formula IV.
[0038] Other preferred compounds according to the invention are
those represented by formulas V-XV, which are within formula I, as
illustrated in Table I.
1 TABLE I Formula R.sub.1 R.sub.2 R.sub.3 M X V 4-SO.sub.3Na
4-SO.sub.3Na CH.sub.3 Ni H.sub.2O VI 4-SO.sub.3Na 4-SO.sub.3Na
CH.sub.3 Co H.sub.2O VII 5-COOH 4-SO.sub.3Na CH.sub.3 Cu H.sub.2O
VIII 5-COOH 4-SO.sub.3Na CH.sub.3 Ni H.sub.2O IX 5-COOH
4-SO.sub.3Na CH.sub.3 Co H.sub.2O X 3-COOH 4-SO.sub.3Na CH.sub.3 Cu
H.sub.2O XI 3-COOH 4-SO.sub.3Na CH.sub.3 Ni H.sub.2O XII 3-COOH
4-SO.sub.3Na CH.sub.3 Co H.sub.2O XIII 4-SO.sub.3Na 4-SO.sub.3Na
COOH Cu H.sub.2O XIV 4-SO.sub.3Na 4-SO.sub.3Na COOH Ni H.sub.2O XV
4-SO.sub.3Na 4-SO.sub.3Na COOH Co H.sub.2O
[0039] As will be apparent to those skilled in the art, the
solubility of the salts of the compounds of formulas I-XV is
greatly influenced by the choice of cation. The preferred cations
for use in the salts are alkali metals, particularly sodium. Mixed
alkali metal salts can of course be used if desired. However,
relatively water-insoluble salts of the invention may be useful as
intermediates in the preparation of more soluble salts.
[0040] A preferred ink jet ink composition of the invention
includes a dye of formulas I and III wherein the metal (M) is
copper, and its salts, especially its alkali metal salts; the
particularly preferred salt being the disodium salt. This disodium
salt has been found to have a combination of properties, including
high solubility and high photostability, which render it especially
advantageous for use as a yellow dye in ink jet inks.
[0041] The dyes of formulas I-XV can be formulated into aqueous
inks using the conventional techniques which are well known to
those skilled in the preparation of such inks. For example, the ink
may contain an alcohol or a glycol as a co-solvent, although the
present dyes are sufficiently water-soluble that the use of
co-solvents is unnecessary. The inks may contain any of the
conventional additives, such as stabilizers, viscosity modifiers,
bactericides, fungicides etc.
[0042] The metal-complexed dyes of formulas I-XV can be prepared by
various synthetic procedures which will be apparent to those
skilled in the art from the discussion which follows and the
specific examples provided below herein. In one preferred synthetic
scheme a solution of a sulfonated anthranilic acid and sodium
nitrite in an acid such as concentrated hydrochloric acid (to form
a diazonium salt) is initially reacted with a solution of an
appropriate pyrazolone compound and sodium acetate in water to form
the uncomplexed azo dye compound which is then isolated.
Subsequently, there is added to a solution of the azo dye and an
alkali-metal acetate, such as sodium acetate, in water a metal
sulfate (or other appropriate metal salt such as acetate, chloride,
etc.) compound such as copper (II) sulfate to form the desired
metal-complexed dye of the invention. In another process for the
preparation of the dyes of the invention, a metal sulfate compound
can be added directly to an ink jet fluid containing the
uncomplexed azo dye thus preparing the metal-complexed dye of the
invention in situ with the attendant advantage of fewer process
steps thus providing overall less expensive ink jet ink fluids.
[0043] Full color ink jet printing requires the use of a set of at
least three different inks, typically at least yellow, cyan and
magenta inks. The inks of the present invention typically have a
very attractive yellow color. It is well known to those skilled in
the artof ink jet printing that, to obtain attractive colors in the
printed images and the wide color gamut that customers,
particularly those engaged in the graphic arts industry, demand it
is important to select the dyes within a set so as to obtain the
best color rendition and gamut, and to ensure that the dyes do not
interact adversely with each other after they have been printed on
a receiver surface. For these reasons, it has been found desirable,
when the dyes of the invention are used as the yellow dye of an ink
jet dye set, to use as the magenta dye of the set a copper complex
of a 1-[phenylazo]naphthalene compound, or a salt thereof, in which
each of the naphthalene and phenyl groups carries a hydroxyl group
ortho to the azo group, at least one of thenaphthalene and phenyl
groups carrying at least one sulfonic acid group. An especially
preferred magenta dye of this type is
3-hydroxy-4-[[2-hydroxy-5-sulfophenyl]azo]-2,7-naphthalenedi-
sulfonic acid, or salt thereof. These compounds are described in
Japanese Published Patent Application (Kokai) No. 02-080470.
[0044] The formulation of ink compositions of the invention, and
the printing apparatus and methods used to carry out ink jet
printing, can be effected using techniques which are well known in
the art. Thus, the dyes of formula I can be formulated into aqueous
ink compositions using conventional techniques which are well known
to those skilled in the preparation of such ink compositions. For
example, the ink composition may contain an alcohol or a glycol as
a co-solvent although the present dyes are sufficiently soluble in
water such that the use of such co-solvents is not necessary. The
ink compositions may contain any suitable additives. Typical
additives for such compositions include stabilizers, viscosity
modifiers, bactericides, fungicides, etc. Typically, a measured
quantity of each ink composition is placed in a separate ink jet
cartridge comprising a housing having walls defining a reservoir
for the ink and an outlet through which the ink leaves the
cartridge and flows to a printhead (typically of the thermal or
piezoelectric type) which provides a stream of droplets of the ink
and directs these droplets to a receiver surface, which typically
is a paper sheet.
EXAMPLES
[0045] The invention will now be described further in detail with
respect to specific preferred embodiments by way of examples, it
being understood that these are intended to be illustrative only
and the invention is not limited to the materials, procedures,
amounts, conditions, etc., recited therein. All parts and
percentages recited are by weight unless otherwise specified.
Example I
[0046] This example describes the synthesis of the compound of
formula IV.
[0047] A sulfonated anthranilic acid, 2-amino-5-sulfo-benzoic acid,
(8 g, 36.8 mmol) and sodium nitrite were dissolved in distilled
water (100 mL) and 14.4 g of concentrated HCL were added. The
solution was stirred for 15 minutes during which time a white
precipitate formed.
[0048] A. In a second flask,
3-methyl-1-(4-sulfophenyl)-2-pyrazo;in-5-one (9.6 g, 37.2 mmol) and
sodium acetate (35 g, 0.33 mole) were dissolved in distilled water
(150 mL) and the diazonium salt mixture was added to the pyrazolone
solution dropwise over about 15 minutes. The mixture was allowed to
stand overnight at 25.degree. C. followed by filtration to recover
the solid 2-[5-hydroxy-3-methyl-1-(4-sulfophenyl)-1H-pyrazol-4-yl
azo]-5-sulfobenzoic acid sodium salt (17 g, 89% yield).
[0049] B(1). The azo dye (10 g, .about.0.02 mole) and sodium
acetate (5 g, .about.0.06 mole) were dissolved in distilled water
(100 mL) and copper(II) sulfate (5 g, 0.02 mole) was added to the
solution followed by stirring until all the copper salt was in
solution. The mixture was allowed to stand overnight during which
time the product crystallized. The solid product was recovered by
filtration, washed with methanol and dried at 60.degree. C. to
yield 8 g of a green solid.
[0050] B(2). Step B was also carried out a second time as follows:
The azo dye (10 g, .about.0.02 mole) and sodium acetate (5g,
.about.0.06 mole) were dissolved in distilled water (100 mL) and
copper(II) sulfate (5 g, 0.02 mole) was added to the solution
followed by stirring until all the copper salt was in solution. The
mixture was allowed to stand overnight. Methanol (25 mL) was added
and the mixture again allowed to stand overnight. The solid was
recovered by filtration and the resulting wet cake was dissolved in
a hot water/methanol (80/20 by volume) solution and allowed to cool
overnight. The solid was recovered by filtration, washed with
methanol and dried at 60.degree. C. to yield a green solid (5.7 g)
An additional amount of solid (3 g) was obtained by adding
additional methanol to the filtrates.
[0051] The product was shown to be about 80% complexed by HPLC
experiments carried out in distilled water (pH 6) at room
temperature. The molecular weight of the dye was found by mass
spectrometry to be 587.7 which is consistent with a 1:1 complexed
structure. The dye was found to have a water solubility of 12.9
mg/mL which is suitable for aqueous ink jet ink formulations and an
extinction coefficient (.epsilon.)=24,588.
Example II
[0052] This example illustrates the light stability of an
uncomplexed azo dye and two metal-complexed dyes of the invention
on three different receiver materials.
[0053] The uncomplexed azo dye (Control) was the product of Step A
of Example I. Metal-complexed Dyes 1 and 2 according to the
invention were 20% and 80% copper complexed compounds of formula
IV, respectively.
[0054] Experiments were carried out with Kodak.RTM. Premium Glossy
Paper (available from Eastman Kodak Company, Rochester, N.Y.),
Epson Premium Glossy Photo Paper (available from Epson Corporation)
and Somerset Radiant White watercolor paper (a 100% cotton fiber
paper with little or no sizing).
[0055] The dye samples were prepared by initially making a
concentrated ink jet fluid (Fluid A) with 35.2% 1,5-pentanediol,
24.8% 2-pyrollidinone, 20% trimethylolpropane and 20% water (by
weight). Two parts by weight of Fluid A were diluted with eight
parts of water to form Fluid B consisting of approximately 7%
1,5-pentanediol, 5% 2-pyrollidinone, 4% trimethylolpropane and 84%
water.
[0056] The test fluids were prepared by dissolving approximately 20
mg of dye with heating and vortex stirring into 1 gram of Fluid B.
Once a clear fluid was obtained, the fluid was coated on the ink
jet receiver material with a #4 Meyer rod. The coating was dried
and the reflection density was measured. When the density was not
in the range of from 0.7 to 1.3 the test fluid was diluted with
additional Fluid B and the coatings repeated until the reflection
density was in the range specified above.
[0057] Samples of the dyes were applied to the papers in a thin
film as described above, air dried and the sample exposed in a
Xenon arc at 10,000 ft. candles and also to cool white fluorescent
bulbs with an irradiance of 2,500 ft. candles. The results are
shown in Tables II and III.
2TABLE II % Density Loss (Y) after 5 Day Xe Arc Dye % Cu Watercolor
Kodak Epson Control 0 -23 -85 -7 1 .about.20 -11 -31 8 2 80 -5 -17
1
[0058]
3TABLE III % Density Loss after 3 weeks under fluorescent light
Paper type Dye % Cu Watercolor Kodak Epson Control 0 -7% -51% 1% 1
20 -2% -15% 1% 2 80 -1% -9% 1%
[0059] It can be seen that Dyes 1 and 2 of formula IV had
significantly better light stability than the uncomplexed azo dye
with respect to all three receiver materials. Further, it can be
seen that between Dyes 1 and 2, Dye 2 which had the higher amount
of copper complexation, had better light stability.
Example III
[0060] This example illustrates the light stability of the dyes of
formulas V-XV in xenon arc testing. The tests were carried out as
described in Example II. The results are shown in Table IV.
4TABLE IV % Density Loss (Y) after 5 Day Xe Arc Dye Watercolor
Kodak Epson V -17 -65 19 VI -19 -52 17 VII -10 -51 7 VIII 2 -56 -4
IX -10 -53 3 X -47 -67 7 XI -11 -11 9 XII -58 -81 5 XIII -2 -10 -1
XIV 0 -2 4 XV -3 -13 -2
Example IV
[0061] This example illustrates the stability to ozone of four
dyes, namely the Control and three metal-complexed dyes according
to the invention, each having a different metal ion as shown in
Table V. Dye 2 has been described previously. Dyes 3 and 4 were
nickel and cobalt complexed dyes, respectively, of formula IV
[0062] The ozone tests were conducted in an ozone chamber
constructed from a large Pyrex jar having a volume of approximately
1.2 ft..sup.3 and a low temperature mercury-argon lamp (Oriel
6035). Ozone was produced in situ by the direct photolysis of
oxygen in the ambient air within the chamber. A fan in the chamber
ensured that all the samples were uniformly exposed to the ozone.
The lamp power supply was energized under the control of a timer
such that the lamp was on for 15 minutes every two hours thereby
producing an average ozone concentration of about 10 PPM (24
mg/m.sup.3). The test was carried out for 16 hours, or 8 lamp
cycles. The ozone tests were carried out on Epson paper. The light
stability experiments were carried out for 5 days at 10,00 ft.
candles on Kodak Glossy Paper.
5 TABLE V % Loss in Density Dye Metal ion Ozone Light Control None
-29% -90% 2 Cu -21% -17% 3 Ni -32% -65% 4 Co -27% -52%
[0063] Typically, images formed on microporous media such as, for
example, Epson Premium Glossy Photo Paper which utilize silicas or
titania to effect rapid dry performance are more susceptible to
attack by ozone and other atmospheric contaminants. One possible
explanation for this phenomenon is that the high surface area and
the oxide surface of such mocroporous media offer catalytic sites
for oxidation by ozone. Images on watercolor paper or Kodak Premium
Glossy Paper typically do not exhibit as much susceptibility to
ozone attack.
[0064] It can be seen from the results shown in Table V that Dye 2,
the copper-complexed dye, had a slightly better resistance to ozone
than the uncomplexed control azo dye and better ozone performance
than Dyes 3 and 4, the nickel- and cobalt-complexed dyes of the
invention. The results also show that Dyes 2-4, the three
metal-complexed dyes of the invention, exhibited better light
stability than the control with Dye 2, the copper-complexed dye,
exhibiting the best light stability.
Example V
[0065] This Example describes experiments carried out to compare
the luminance (L*), chroma (c*) and hue (h*) of images formed on
various receiver materials with Dye 2 of the invention with those
of current commercially available digital printing systems.
[0066] The commercially available printing systems were tested by
using a digital file of a step-wedge color test target. The test
fluid including Dye 2 of the invention was prepared as described in
Example II and was applied to the various receiver papers as
described in that example.
[0067] The densitometry and colorimetry measurements were made on a
Gretag MacBeth SMP-50 densitometer which provided the L* , c* and
h* as part of the measurement of the reflection density. These
numbers were then tabulated and compared with commercial yellow
dyes.
6 TABLE VI System L* c* h* HP P1000 88 61 100 Epson 870 91 56 103
Fuji Thermal Autochrome 84 61 97 Sony D2T2 93 63 106 Noritsu RA4 84
50 95 Shinko D2T2 93 68 106 Dye 2/Epson Paper 90 62 102 Dye 2/Kodak
Paper 88 57 99 Dye 2//Watercolor 90 68 96
[0068] It can be seen that the copper-complexed dye of the
invention exhibited luminance, chroma and hue values which are
comparable to those obtained from the commercially available
systems.
Example VI
[0069] This example describes experiments carried out to compare
the luminance (L*) of images formed on Epson 870 paper with Dye 2
of the invention with those images formed on Epson 870 paper with
the dyes of formulas IV-VIII and XIII-XV. The luminance values,
including the a* and b*, values were obtained as described in
Example V.
7 TABLE VII Formula L* a* b* Dye 2 90 IV 87 -9 78 V 86 -5 83 VI 88
-8 81 VII 88 -11 79 VIII 87 -10 78 XIII 85 -7 88 XIV 82 1 89 XV 81
2 86
[0070] These data show that the images formed with the dyes of
formulas IV-VIII and XIII-XV were comparable to that formed with
the dye of formula IV.
[0071] Although the invention has been described in detail with
respect to various preferred embodiments, it is not intended to be
limited thereto, but rather those skilled in the art will recognize
that variations and modifications are possible which are within the
spirit of the invention and the scope of the appended claims.
* * * * *